1. Field of the Invention
The invention relates to electronic technologies, and, more precise, to devices for controlling intensity, color, phase, polarization or direction of light, in particular, to flexible displays.
2. Description of the Related Art
Flexible displays (e.g., liquid crystal, organic, electroluminescent, electrochromic) include plastic or metal substrates with electrodes and driving microcircuits on their interior surfaces. Between substrates are paddings, otherwise known as spacers. Substrates of flexible displays normally have flat surfaces.
Spacers are used for maintenance of the uniform clearance between the substrates and to assemble the substrates together. Spacers may also be used for diminution and the uniform redistribution of pressure over the surface of the substrate, such as from an external force. The spacers may be made as glass balls, hard polymeric blobs or columns grown and/or deposited on substrates. A liquid crystal display may include spacers in the form of uniform or non-uniform elements (e.g.,) blobs which are located between two flat substrates.
For redistribution of the pressure arising on a surface of the substrates and to minimize effects of a change of pressure in the active field or area of the display, a system of periodic dimples or channels may also be used. A liquid crystal display with two substrates may include dimples arranged in a periodic system on the substrates.
Another type of display contains two substrates with flat inner surfaces. On the one substrate, a set of the unidirectional channels (e.g., grooves) is located. These channels and the clearance between the substrates are filled by cholesteric liquid crystals for improvement of optical performance of the display. Spacers are located between the substrates without a link to channels position.
In displays with flat substrates and spacers, an exterior action (e.g., external force) on the display panel, in particular, a bend, can result in spacers disordering or moving to undesirable locations. Accordingly, increased clearance between substrates may be caused by the displaced spacers. Such disordering is caused by the lack of reliable fixation of the spacers. Moreover, there is a chance that a substrate would be separated or detached from the spacers when the external force is applied to the display. A substrate may separate from the spacers due to a stretching of both surfaces of the substrates (such as, increase of the upper substrate and decrease of the lower substrate), which leads to breaking of the links or connection between a substrate and a spacer.
Other disadvantages may include cracking and/or tearing of the electrodes and/or other hard coats fixed to the surface of substrates when an external force is applied and the display is bent. The cracking or tearing is often pronounced in places of contact of an electrode with the spacers, applying additional pressure (e.g., overload) on the electrodes. The above drawbacks decrease reliability of the display and the picture quality under the impact of an outside force.